Collared lizard

Collared lizard
Name	Collared lizard
Genus	Crotaphytus
Species	C. spp.

Collared lizard is a common name for a group of North American lizards in the genus Crotaphytus known for bold patterning, facultative bipedal locomotion, and territorial behavior. First described in 19th-century herpetological surveys alongside specimens collected during western expeditions, these lizards have been subjects of field studies by institutions such as the Smithsonian Institution, American Museum of Natural History, and universities including University of Arizona and University of Texas at Austin. Their conspicuous appearance and ecological role have made them topics in natural history works tied to regions like the Sonoran Desert, Chihuahuan Desert, and Mojave Desert.

Taxonomy and Nomenclature

The genus Crotaphytus was established in early systematic treatments influenced by naturalists and taxonomists associated with collections from expeditions by figures like John C. Frémont, Charles Darwin (in comparative context), and later cataloguers at the British Museum. Species-level names reflect descriptions published in journals tied to organizations such as the Linnean Society of London and the American Society of Ichthyologists and Herpetologists. Molecular phylogenetics using techniques developed in laboratories at institutions like Harvard University, University of California, Berkeley, and Arizona State University has refined relationships among Crotaphytus, placing them in a clade with other iguanian taxa and prompting revisions debated in forums such as meetings of the Society for the Study of Amphibians and Reptiles.

Description and Identification

Adults are robust, with sexually dimorphic coloration noted in monographs produced by field researchers from Texas A&M University and the University of New Mexico. Diagnostic characters used by curators at the National Museum of Natural History include head shape, dorsal patterning, scale counts, and the distinctive neck bands for which the group is colloquially named; these traits are catalogued in keys similar to those published by the Field Museum and the Royal Ontario Museum. Size ranges are recorded in surveys undertaken by herpetology groups at institutions like the California Academy of Sciences and the Denver Museum of Nature & Science, and photographic guides from organizations such as the National Audubon Society and the British Herpetological Society illustrate typical morphs. Color polymorphism, melanism, and sex-specific displays have been analyzed in ecological studies affiliated with the University of Colorado, University of California, Los Angeles, and the Rocky Mountain Biological Laboratory.

Distribution and Habitat

Populations occur across arid and semi-arid regions mapped by agencies including the United States Geological Survey and state natural heritage programs in Arizona, New Mexico, Texas, and Colorado; ranges extend into northern Mexico regions administered under bodies like the Comisión Nacional para el Conocimiento y Uso de la Biodiversidad. Habitats include rocky outcrops, canyonlands, and scrub dominated landscapes characterized in regional floras published by the Missouri Botanical Garden and the Royal Botanic Gardens, Kew. Biogeographic analyses referencing datasets from the Global Biodiversity Information Facility and the International Union for Conservation of Nature illustrate distribution limits shaped by climatic factors reported in studies from the Intergovernmental Panel on Climate Change and paleoclimatic reconstructions associated with the National Oceanic and Atmospheric Administration.

Behavior and Ecology

Territorial defense, display behavior, and predator avoidance have been documented in field experiments conducted at research stations such as the Desert Laboratory on Tumamoc Hill and the University of Arizona Desert Laboratory. Diet studies by ecologists at New Mexico State University and Arizona State University show insectivory supplemented by occasional small vertebrates, reflecting trophic interactions discussed in journals associated with the Ecological Society of America and the Journal of Herpetology. Locomotor biomechanics, including sprinting and bipedal running, were quantified in biomechanics labs at Stanford University and University of California, Berkeley, with implications for functional morphology debated at conferences hosted by the Society for Integrative and Comparative Biology. Predator–prey dynamics involving raptors catalogued by the Cornell Lab of Ornithology, mammalian carnivores recorded by the Smithsonian Conservation Biology Institute, and parasitological surveys undertaken by the Centers for Disease Control and Prevention further contextualize their ecological role.

Reproduction and Life Cycle

Breeding seasons and nesting behaviors have been recorded in field studies supported by agencies like the National Science Foundation and universities including University of Texas at El Paso. Clutch size, egg incubation periods, and hatchling growth rates are described in captive studies reported by zoo programs at the San Diego Zoo, Phoenix Zoo, and university herpetoculture facilities such as those at Ohio State University. Life-history parameters derived from mark–recapture studies curated by the US Fish and Wildlife Service inform population models similar to those used by analysts at the World Wildlife Fund and conservation biologists publishing in journals affiliated with the Society for Conservation Biology.

Conservation and Threats

Conservation status assessments by regional agencies, the IUCN Red List, and state wildlife departments evaluate threats including habitat loss from energy development documented by the Department of Energy, fragmentation due to transportation projects overseen by the Federal Highway Administration, and illegal collection monitored by enforcement bodies like US Fish and Wildlife Service law enforcement. Climate change projections from the Intergovernmental Panel on Climate Change and land-use data provided by the United Nations Environment Programme inform vulnerability analyses conducted by NGOs such as Nature Conservancy and research groups at the National Center for Atmospheric Research. Management recommendations in recovery plans draw on interdisciplinary collaborations among universities, government agencies, and conservation organizations including the Bureau of Land Management and state parks systems.

Category:Reptiles of North America